I2c write&read

[MINHLE]

Hi every one,
i ahce a problem with writing and reading using I2C WRITE...

thansk for any help,
-----------------

here is the connection:

pic16f628: porta.6 and 7 are SDA & SCL

24lc256 (8 bit EEPROM): A0,1,2,3,4 and WP: ground
SDA &SCL connected 10k to 5V...
------------------------
;the program:


CMCON = 1
TRISA = %11000000 ; set port A6,7 to input (SDA & SLC)
TRISB = 0
DPin var PORTA.6 ' I2C data pin
Cpin var PORTA.7 ' I2C clock pin

I var byte
S VAR BYTE
b1 var byte
k var byte

B0 var byte

i = 0
b0 = 0

while b0 != $ff
lookup I, [$3F,$48,$48,$48,$3F,$3F,$00,$ff],B0 ;put a value into
;B0
I2CWRITE DPIN,CPIN,$A0,i,[B0] ' Write B0 to address I

Pause 10 ' Delay 10ms after each write
i = i+1 ' increase the address by 1
wend
loop:
;reading process
b1 = 0 ; clear b1
while b1 !=$ff
I2CREAD DPIN,CPIN,$A1,i,[B1]

FOR K = 0 TO 63 ; scan for 64 times
CALL RESET
PORTB = b1
CALL DELAY

NEXT K
i = i +1
wend
goto loop
end
RESET: PORTA.1 = 1 ;RESET 4017
@NOP
PORTA.1 = 0
RETURN

DELAY: pause 10
portb = 0 ; reset portb
porta.0 = 1 ; clock the 4017
@nop
porta.0 = 0
return

[Gusse]

Read this thread: I2CRead & I2CWrite not working as expected

BR,
-Gusse-

[MINHLE]

thanks for your words,

i checked but it is ok, the device is 8 bit size. and the address is variable..
all are defined by BYTE.
i.e i = 0 to 10 ;(i : location in the EEPROM)


thanks agains
MInhle

[Gusse]

Hi MInhle,

Check once more the thread and do like Melanie advices!

Define I2CDevice as a BYTE, not a constant.
Define I2CAddress as a WORD (your EEPROM is >16k and therefore variable must be a word)

Example:
I2CWrite SDA,SCL,I2CDevice,I2CAddress,[DataA]

BR,
-Gusse-

[Melanie]

10K is also a little high... drop it by at least half to say 4K7.

[MINHLE]

Hello All,

the deviec is 16f628. the OSC 20Mhz (internal OSC, so R is ~10k-12K)
and the 24lc256 is BYTE SIZE. (32K X8 BIT)
the address is variable.

i will change to 4.7k and redefine eeprom address.

however the fuse defined: (work well )

OSC: INTRO CLOCKOUT
MCLR: INPUT PIN
(all other defined in the fuse window: marain unchange)

thank for all

regards,